In the context of medical treatment it often is necessary to regularly change the orientation of a bed-ridden patient. For example, changing the orientation of a bed-ridden patient can be helpful in preventing the patient from developing bed sores or from lapsing into a comatose condition. It may also be used to help stimulate the patient's circulation. With conventional hospital beds, however, changing the orientation of a patient must be done manually and is therefore quite labor intensive and costly.
A "bed" which allows for automatic adjustment of the orientation of a patient is disclosed in DE 3,915,420 A1. With the disclosed "bed" a patient is placed within a rigid shell which is equipped with inflatable air chambers. In order to enable the orientation of the patient to be adjusted, the shell can be rotated by a pair of engine driven axles. As the shell is rotated, the inflatable air chambers support the body of the patient, thereby preventing the possibility of injury. The inflatable air chambers, however, limit air circulation within the shell and make it difficult for the patient to breathe. Moreover, the noise and vibration caused by the engines which rotate the shell can make the bed quite uncomfortable. Thus, this type of apparatus is particularly ill-suited for use in the context of medical treatment.